Unless your tank is pH 7 or less and you have soft water with very low nitrates I wouldn't keep Blue Rams, I have just changed my whole set up to allow me to keep Rams and still one died despite perfect conditions for them. They are very sensitive fish. Bolivian Rams on the other hand are pretty hardy, mine do really well and are pretty colourful. I agree German Rams are prettier but Bolvian Rams aren't to bad to look at, just have a search around and find a really nice pair.
If your tank is recently cycled I think you will just be giving German Rams a death sentence if you buy them now. If you have the right water condition and still have your heart set on german rams i'd but them in a few months time.